Broadband Interference Direction Finding And ADBF Techniques For Shaped Antennas

Compared with traditional antennas,phased array antennas are widely used in electronic fields such as radar and communication due to their strong anti-interference ability.Adaptive Digital Beam Forming(ADBF)technology is one of the key technologies of phased array antennas.Theoretical analysis shows that the adaptive beam forming algorithm has good performance,but it has many influences and constraints in engineering practice.Direction of arrival estimation is also one of the key technologies.According to a specific receiving antenna array model,high-resolution direction finding in engineering can be achieved.Beamforming of phased array antennas is widely used in engineering practice,especially for satellite communication.Shaped antennas expand the airspace coverage while ensuring high gain.However,with the increase of communication rates,the bandwidth of communication receivers is also increasing.For broadband signal,combined with interference orientation and ADBF technology to improve its anti-interference ability has become a difficult problem.In response to this difficulty,high-resolution direction finding and adaptive beam nulling algorithms for broadband interference signals are studied in this thesis,also ADBF and broadband anti-jamming performance evaluation techniques for shaped antennas.The specific contents and innovations are as follows:Firstly,for broadband anti-jamming,space-frequency joint anti-jamming algorithm and space-time joint anti-jamming algorithm for shaped antenna are introduced.The simulation results show that the space-time method has better anti-jamming ability,which is reflected in the fact that the space-time method can resist more broadband interference,and at the same time,the null in the interference direction is deeper.Then,the simulation and comparison experiments of the space-time joint anti-jamming algorithm used for the shaped antenna and the ordinary space algorithm are carried out.Improving the degree of freedom of the system without increasing the number of array elements.Secondly,for the shaped antenna,this thesis studies the applicability of the Incoherent Signal-Subspace Method(ISSM)and the Coherent Signal-Subspace Method(CSSM),and analyzes and compares the two algorithms to measure.The simulation results show that the direction finding accuracy of the two algorithms has a high level without considering the amplitude and phase errors,and the resolution of the ISSM algorithm is relatively high after adding the amplitude and phase errors,the direction finding effect is good.The error robustness simulation experiment results of the two algorithms show that the performance of the ISSM algorithm is better than that of the CSSM algorithm.The simulation results of the time complexity of the two algorithms show that the running time of the ISSM algorithm increases correspondingly with the increase of the number of sampling points,and the algorithm complexity is higher.Finally,combined with the system engineering theory,this thesis introduces a set of antijamming performance evaluation methods for shaped antennas,and set the software simulation platform.The platform can not only score the existing broadband anti-jamming methods,but also realize dynamic decision-making in actual combat,and effectively counter the surrounding interference environment in real time.At the same time,for unknown types of electronic countermeasures,the updated data can be expanded into the local library by means of "training and learning".